Dosimetric Comparison of Intracavitary Versus Combined Intracavitary-Interstitial Image-Guided Brachytherapy in Locally Advanced Cervical Cancer

Purpose The present study aimed to compare the dose distributions between conventional three-catheter intracavitary (IC) brachytherapy and combined intracavitary–interstitial (IC/IS) brachytherapy in the management of locally advanced cervical cancer (LACC). Materials and Methods A retrospective dosimetric analysis was performed using data from 78 patients with cervical cancer who underwent high-dose-rate (HDR) brachytherapy. To evaluate the dosimetric advantages of IC/IS brachytherapy, patients were stratified into two groups: those treated with IC brachytherapy and those treated with IC/IS brachytherapy. Dosimetric parameters between the two groups were compared. Results In the IC/IS brachytherapy group, V150 values for the high-risk clinical target volume (HR-CTV) were significantly higher than those in the IC group ( p < 0.001). Subsequent comparison of organ-at-risk (OAR) dosimetric parameters revealed that D 0.1 cc, D 1 cc, D 2 cc, D 5 cc, and D 10 cc values for the bladder and sigmoid colon were significantly lower in the IC/IS group than in the IC group (all p < 0.05). Conclusions Compared with conventional IC brachytherapy, combined IC/IS brachytherapy provides superior HR-CTV coverage with higher doses while simultaneously reducing radiation exposure to the bladder and sigmoid colon, provided that the D90 dose constraint for the HR-CTV is met.